Process for producing modified phenolic resin bonding agents and use thereof for producing particle board

US5011886A · kind A · utility

Assignee

• RWE-DEA Aktiengesellschaft fur Mineraloel und Chemie · DE

Inventors

• Adolf Buschfeld
• Matthias Lattekamp · Alpen, DE
• Gerd Ripkens · Kamp-Lintfort, DE
• Hans-Heinz Schittek

Key dates

• Filing date: Feb 26, 1990
• Grant date: Apr 30, 1991
• Expiry date: Feb 26, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G14/08
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The inventive concept is to condense the phenol formaldehyde resins to a higher molecular weight than usual so far. Subsequent addition of urea thereto reduces viscosity to normal levels and increases solid content. The added urea does not take part in condensation reaction but partly reacts in the alkaline medium with formaldehyde to methylol urea (in a so called equilibrium reaction), which is formaldehyde donor for the phenol formaldehyde crosslinking reaction during the pressing of the particle board. The present invention relates to a process for producing modified phenolic resin bonding agents, characterized by preparing as known per se phenol-formaldehyde resins with a viscosity of more than 300 mPa.s (at 20.degree. C.) and with a solids content of from 65 weight percent and adding to the viscous phenolic resin solutions obtained 5 to 50 weight percent urea, based on the weight of the phenolic resin solution, the phenol formaldehyde resins being prepared with as much alkali as is required to secure that the modified resin solution resulting therefrom contains 2 to 12 weight percent total alkali calculated as NaOH. The solids content of the modified resin solutions ranges of …